Commit efe97112 authored by Neal Liu's avatar Neal Liu Committed by Rafael J. Wysocki
Browse files

cpuidle: change enter_s2idle() prototype 



Control Flow Integrity(CFI) is a security mechanism that disallows
changes to the original control flow graph of a compiled binary,
making it significantly harder to perform such attacks.

init_state_node() assign same function callback to different
function pointer declarations.

static int init_state_node(struct cpuidle_state *idle_state,
                           const struct of_device_id *matches,
                           struct device_node *state_node) { ...
        idle_state->enter = match_id->data; ...
        idle_state->enter_s2idle = match_id->data; }

Function declarations:

struct cpuidle_state { ...
        int (*enter) (struct cpuidle_device *dev,
                      struct cpuidle_driver *drv,
                      int index);

        void (*enter_s2idle) (struct cpuidle_device *dev,
                              struct cpuidle_driver *drv,
                              int index); };

In this case, either enter() or enter_s2idle() would cause CFI check
failed since they use same callee.

Align function prototype of enter() since it needs return value for
some use cases. The return value of enter_s2idle() is no
need currently.

Signed-off-by: default avatarNeal Liu <neal.liu@mediatek.com>
Reviewed-by: default avatarSami Tolvanen <samitolvanen@google.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 81f94ddf

drivers/acpi/processor_idle.c

+4 −2
Original line number Diff line number Diff line
@@ -655,7 +655,7 @@ static int acpi_idle_enter(struct cpuidle_device *dev, 
	return index;

}



static void acpi_idle_enter_s2idle(struct cpuidle_device *dev,

static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,

				  struct cpuidle_driver *drv, int index)

{

	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
@@ -674,6 +674,8 @@ static void acpi_idle_enter_s2idle(struct cpuidle_device *dev, 
		}

	}

	acpi_idle_do_entry(cx);



	return 0;

}



static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,

drivers/cpuidle/cpuidle-tegra.c

+5 −3
Original line number Diff line number Diff line
@@ -253,11 +253,13 @@ static int tegra_cpuidle_enter(struct cpuidle_device *dev, 
	return err ? -1 : index;

}



static void tegra114_enter_s2idle(struct cpuidle_device *dev,

static int tegra114_enter_s2idle(struct cpuidle_device *dev,

				 struct cpuidle_driver *drv,

				 int index)

{

	tegra_cpuidle_enter(dev, drv, index);



	return 0;

}



/*

drivers/idle/intel_idle.c

+4 −2
Original line number Diff line number Diff line
@@ -173,13 +173,15 @@ static __cpuidle int intel_idle(struct cpuidle_device *dev, 
 * Invoked as a suspend-to-idle callback routine with frozen user space, frozen

 * scheduler tick and suspended scheduler clock on the target CPU.

 */

static __cpuidle void intel_idle_s2idle(struct cpuidle_device *dev,

static __cpuidle int intel_idle_s2idle(struct cpuidle_device *dev,

				       struct cpuidle_driver *drv, int index)

{

	unsigned long eax = flg2MWAIT(drv->states[index].flags);

	unsigned long ecx = 1; /* break on interrupt flag */



	mwait_idle_with_hints(eax, ecx);



	return 0;

}



/*

include/linux/cpuidle.h

+6 −3
Original line number Diff line number Diff line
@@ -65,8 +65,11 @@ struct cpuidle_state { 
	 * CPUs execute ->enter_s2idle with the local tick or entire timekeeping

	 * suspended, so it must not re-enable interrupts at any point (even

	 * temporarily) or attempt to change states of clock event devices.

	 *

	 * This callback may point to the same function as ->enter if all of

	 * the above requirements are met by it.

	 */

	void (*enter_s2idle) (struct cpuidle_device *dev,

	int (*enter_s2idle)(struct cpuidle_device *dev,

			    struct cpuidle_driver *drv,

			    int index);

};

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